diff --git a/bootstrap.ps1 b/bootstrap.ps1
index 5cd5aa1..0b118a0 100644
--- a/bootstrap.ps1
+++ b/bootstrap.ps1
@@ -185,7 +185,9 @@ function Write-Log {
         default { Write-Host $logMessage }
     }
 
-    Add-Content -Path $LogFile -Value $logMessage -ErrorAction SilentlyContinue
+    if (-not $DryRun) {
+        Add-Content -Path $LogFile -Value $logMessage -ErrorAction SilentlyContinue
+    }
 }
 
 function Add-SummaryItem {
@@ -1527,8 +1529,8 @@ try {
     }
     elseif (-not (Test-Path $RegistryConfig)) {
         Write-Log "WARNING: registry.json not found at $RegistryConfig" -Level WARNING
-        Add-SummaryItem -Step "Registry" -Status "WARN" -Message "registry.json not found"
-        Set-StepState -StepId $stepId -Status "done" -Message "registry.json not found"
+        Add-SummaryItem -Step "Registry" -Status "SKIP" -Message "registry.json not found"
+        Set-StepState -StepId $stepId -Status "skipped" -Message "registry.json not found"
     }
     elseif (-not (Test-Path $RegistryScript)) {
         Write-Log "ERROR: Registry apply script not found at $RegistryScript" -Level ERROR
@@ -1637,8 +1639,8 @@ try {
     }
     elseif (-not (Test-Path $OptionalAppsJson)) {
         Write-Log "optional-apps.json not found at $OptionalAppsJson - skipping optional apps shortcut" -Level INFO
-        Add-SummaryItem -Step "Optional Apps Shortcut" -Status "WARN" -Message "optional-apps.json not found"
-        Set-StepState -StepId $stepId -Status "done" -Message "optional-apps.json not found"
+        Add-SummaryItem -Step "Optional Apps Shortcut" -Status "SKIP" -Message "optional-apps.json not found"
+        Set-StepState -StepId $stepId -Status "skipped" -Message "optional-apps.json not found"
     }
     else {
         try {
@@ -1669,8 +1671,8 @@ try {
     elseif (-not (Test-Path $OptionalAppsJson)) {
         if ($OptionalAppsOnly) {
             Write-Log "WARNING: optional-apps.json not found at $OptionalAppsJson" -Level WARNING
-            Add-SummaryItem -Step "Optional Apps" -Status "WARN" -Message "optional-apps.json not found"
-            Set-StepState -StepId $stepId -Status "done" -Message "optional-apps.json not found"
+            Add-SummaryItem -Step "Optional Apps" -Status "FAIL" -Message "optional-apps.json not found"
+            Set-StepState -StepId $stepId -Status "failed" -Message "optional-apps.json not found"
         }
     }
     else {
diff --git a/modules/BootstrapRun.ps1 b/modules/BootstrapRun.ps1
index 51e4eb8..07304f1 100644
--- a/modules/BootstrapRun.ps1
+++ b/modules/BootstrapRun.ps1
@@ -69,6 +69,8 @@ function Save-State {
         [string]$StatePath
     )
 
+    if ($DryRun) { return }
+
     $State.lastUpdated = (Get-Date).ToString("o")
     $State | ConvertTo-Json -Depth 6 | Set-Content -Path $StatePath -Force
 }
@@ -85,6 +87,8 @@ function Set-StepState {
         [string]$Message
     )
 
+    if ($DryRun) { return }
+
     if (-not $SetupState.steps.Contains($StepId)) {
         $SetupState.steps[$StepId] = [pscustomobject]@{
             status = "pending"
@@ -120,6 +124,11 @@ function Should-RunStep {
         return $true
     }
 
+    # Older runs incorrectly completed this step when the optional input was absent.
+    if ($StepId -eq 'optionalShortcut' -and $SetupState.steps[$StepId].message -eq 'optional-apps.json not found') {
+        return $true
+    }
+
     return $SetupState.steps[$StepId].status -ne "done"
 }
 
@@ -134,6 +143,8 @@ function Update-SetupProgress {
         [switch]$ResetPackage
     )
 
+    if ($DryRun) { return }
+
     if ($PSBoundParameters.ContainsKey('Phase')) {
         $script:ProgressState.phase = $Phase
     }
diff --git a/modules/WinGetInstall.ps1 b/modules/WinGetInstall.ps1
index e4637e9..d33d365 100644
--- a/modules/WinGetInstall.ps1
+++ b/modules/WinGetInstall.ps1
@@ -308,8 +308,8 @@ function Invoke-WingetManifestInstall {
 
     if (-not (Test-Path $ManifestPath)) {
         Write-Log "WARNING: $ManifestLabel not found at $ManifestPath - skipping application import" -Level WARNING
-        Add-SummaryItem -Step $SummaryStep -Status "WARN" -Message $MissingManifestMessage
-        Set-StepState -StepId $StepId -Status "done" -Message $MissingManifestMessage
+        Add-SummaryItem -Step $SummaryStep -Status "FAIL" -Message $MissingManifestMessage
+        Set-StepState -StepId $StepId -Status "failed" -Message $MissingManifestMessage
         return $false
     }
 
diff --git a/tests/BootstrapInputsPreview.Tests.ps1 b/tests/BootstrapInputsPreview.Tests.ps1
new file mode 100644
index 0000000..3d7aeb5
--- /dev/null
+++ b/tests/BootstrapInputsPreview.Tests.ps1
@@ -0,0 +1,141 @@
+BeforeAll {
+    $repoRoot = Split-Path $PSScriptRoot -Parent
+    $bootstrapPath = Join-Path $repoRoot 'bootstrap.ps1'
+    $tokens = $null
+    $parseErrors = $null
+    $bootstrapAst = [Management.Automation.Language.Parser]::ParseFile($bootstrapPath, [ref]$tokens, [ref]$parseErrors)
+    if ($parseErrors) { throw ($parseErrors | Out-String) }
+    $main = $bootstrapAst.EndBlock.Statements | Where-Object { $_ -is [Management.Automation.Language.TryStatementAst] }
+    foreach ($name in @('Write-Log', 'New-DesktopShortcut', 'Get-RunBootstrapTarget')) {
+        $definition = $bootstrapAst.Find({ param($node)
+            $node -is [Management.Automation.Language.FunctionDefinitionAst] -and $node.Name -eq $name
+        }, $false)
+        . ([scriptblock]::Create($definition.Extent.Text))
+    }
+    . (Join-Path $repoRoot 'modules/BootstrapRun.ps1')
+    . (Join-Path $repoRoot 'modules/WinGetInstall.ps1')
+    $registryStep = [scriptblock]::Create(($main.Body.Statements | Where-Object { $_.Extent.Text.StartsWith('if ($OptionalAppsOnly)') -and $_.Extent.Text.Contains('Step 5:') }).Extent.Text)
+    $optionalShortcutStep = [scriptblock]::Create(($main.Body.Statements | Where-Object { $_.Extent.Text.StartsWith('if ($OptionalAppsOnly)') -and $_.Extent.Text.Contains('Step 8:') }).Extent.Text)
+    $optionalAppsStep = [scriptblock]::Create(($main.Body.Statements | Where-Object { $_.Extent.Text.StartsWith('if (-not (Should-RunStep') -and $_.Extent.Text.Contains('Step 9:') }).Extent.Text)
+}
+
+Describe 'Missing bootstrap inputs' {
+    BeforeEach {
+        $DryRun = $false
+        $Force = $false
+        $OptionalAppsOnly = $false
+        $StateFile = Join-Path $TestDrive 'state.json'
+        $SetupState = Initialize-State -StatePath (Join-Path $TestDrive 'unused.json') -StepIds @('winget', 'registry', 'optionalShortcut', 'optionalWinget')
+        $SummaryItems = [Collections.Generic.List[object]]::new()
+        $FailedItems = [Collections.Generic.List[object]]::new()
+        $RunStepIds = @('winget', 'registry', 'optionalShortcut')
+        $RunStartedAt = (Get-Date).ToString('o')
+        $ConfigRoot = $TestDrive
+        $desktopPath = $TestDrive
+        $RegistryConfig = Join-Path $TestDrive 'registry.json'
+        $RegistryScript = Join-Path $TestDrive 'apply-registry.ps1'
+        $OptionalAppsJson = Join-Path $TestDrive "optional-apps-$([guid]::NewGuid()).json"
+        Mock Write-Log { }
+        Mock Update-SetupProgress { }
+        Mock Test-WingetPackageInstalled { $true }
+        Mock Invoke-WingetPackageInstall { throw 'Unexpected installer' }
+        Mock New-DesktopShortcut { }
+        Mock Get-RunBootstrapTarget { Join-Path $TestDrive 'bootstrap.ps1' }
+    }
+
+    It 'fails missing automatic apps and reconciles them when added on an ordinary rerun' {
+        $manifestPath = Join-Path $TestDrive 'apps.json'
+        $markerPath = Join-Path $TestDrive 'winget.completed'
+        $installArgs = @{ ManifestPath = $manifestPath; StepId = 'winget'; SummaryStep = 'WinGet'; MarkerPath = $markerPath; ManifestLabel = 'apps.json'; MissingManifestMessage = 'apps.json not found' }
+        Invoke-WingetManifestInstall @installArgs | Should -BeFalse
+        $SetupState.steps.winget.status | Should -Be 'failed'
+        Test-Path $markerPath | Should -BeFalse
+        Should -Invoke Test-WingetPackageInstalled -Times 0 -Exactly
+
+        '{"Sources":[{"Packages":[{"PackageIdentifier":"Example.App"}]}]}' | Set-Content $manifestPath
+        $SetupState = Initialize-State -StatePath $StateFile -StepIds @('winget')
+        Should-RunStep winget | Should -BeTrue
+        Invoke-WingetManifestInstall @installArgs | Should -BeTrue
+        $SetupState.steps.winget.status | Should -Be 'done'
+        Should -Invoke Test-WingetPackageInstalled -Times 1 -Exactly
+    }
+
+    It 'skips absent registry configuration and applies it once supplied' {
+        $stepId = 'registry'
+        . $registryStep
+        $SetupState.steps.registry.status | Should -Be 'skipped'
+        $SummaryItems[-1].Status | Should -Be 'SKIP'
+        '{}' | Set-Content $RegistryConfig
+        '[pscustomobject]@{ Failed = 0 }' | Set-Content $RegistryScript
+        $SetupState = Initialize-State -StatePath $StateFile -StepIds @('registry')
+        . $registryStep
+        $SetupState.steps.registry.status | Should -Be 'done'
+        $SetupState.steps.registry.message | Should -Be 'Registry fallback applied'
+    }
+
+    It 'retries absent optional shortcuts, including old incorrectly completed records' {
+        $stepId = 'optionalShortcut'
+        Set-StepState -StepId $stepId -Status done -Message 'optional-apps.json not found'
+        . $optionalShortcutStep
+        $SetupState.steps.optionalShortcut.status | Should -Be 'skipped'
+        Should -Invoke New-DesktopShortcut -Times 0 -Exactly
+        '{}' | Set-Content $OptionalAppsJson
+        $SetupState = Initialize-State -StatePath $StateFile -StepIds @('optionalShortcut')
+        . $optionalShortcutStep
+        $SetupState.steps.optionalShortcut.status | Should -Be 'done'
+        Should -Invoke New-DesktopShortcut -Times 1 -Exactly
+        Should-RunStep optionalShortcut | Should -BeFalse
+    }
+
+    It 'fails an explicitly requested optional installation when its manifest is missing' {
+        $stepId = 'optionalWinget'
+        $OptionalAppsOnly = $true
+        $RunStepIds = @('optionalWinget')
+        . $optionalAppsStep
+        $SetupState.steps.optionalWinget.status | Should -Be 'failed'
+        (Get-BootstrapRunResult).ExitCode | Should -Be 1
+        Should-RunStep optionalWinget | Should -BeTrue
+    }
+}
+
+Describe 'Bootstrap dry-run isolation in Windows PowerShell' {
+    It 'preserves all saved results with <Label>' -ForEach @(
+        @{ Label = 'DryRun'; ExtraArgs = @() }
+        @{ Label = 'DryRun and Force'; ExtraArgs = @('-Force') }
+        @{ Label = 'DryRun and PromptRestart'; ExtraArgs = @('-PromptRestart') }
+    ) {
+        $runtime = New-Item -ItemType Directory -Path (Join-Path $TestDrive ([guid]::NewGuid().ToString()))
+        $StateFile = Join-Path $runtime.FullName 'state.json'
+        $DryRun = $false
+        $ids = @('winget', 'repo', 'sophia', 'postInstallTweaks', 'registry', 'shortcut', 'restoreShortcut', 'optionalShortcut', 'optionalWinget', 'summary')
+        $SetupState = Initialize-State -StatePath $StateFile -StepIds $ids
+        foreach ($id in $ids) {
+            $SetupState.steps[$id].status = 'done'
+            $SetupState.steps[$id].message = 'Previously completed'
+        }
+        Save-State -State $SetupState -StatePath $StateFile
+        foreach ($name in @('progress.json', 'install.log', 'failed-installs.log', 'sophia.completed', 'winget.completed', 'optional-winget.completed', 'Setup Summary.txt', 'Failed Installs.txt')) {
+            'Previous authoritative result' | Set-Content (Join-Path $runtime.FullName $name)
+        }
+        $before = @(Get-ChildItem $runtime.FullName -File | Sort-Object Name | Get-FileHash | Select-Object Path, Hash) | ConvertTo-Json
+
+        # Run the production script in a child host with disposable paths and an
+        # administrator-check substitute. Any attempt to invoke setup work fails.
+        $source = $bootstrapAst.Extent.Text.Replace('#Requires -RunAsAdministrator', '')
+        $source = $source.Replace('$SetupPath = "C:\Setup"', ('$SetupPath = ' + "'$($runtime.FullName)'"))
+        $source = $source.Replace('$ModuleRoot = Join-Path $PSScriptRoot "modules"', ('$ModuleRoot = ' + "'$(Join-Path $repoRoot 'modules')'"))
+        $adminAssignment = $main.Body.Statements | Where-Object { $_ -is [Management.Automation.Language.AssignmentStatementAst] -and $_.Left.Extent.Text -eq '$isAdmin' }
+        $guards = @('Invoke-WingetManifestInstall', 'Get-BackupManifestData', 'Ensure-CanonicalRepo', 'Get-SophiaScript', 'Invoke-PostInstallTweaks', 'New-DesktopShortcut', 'Read-Host', 'Restart-Computer') | ForEach-Object {
+            "function $_ { throw 'Dry run invoked $_' }"
+        }
+        $source = $source.Replace($main.Extent.Text, (($guards -join "`n") + "`n" + $main.Extent.Text))
+        $source = $source.Replace($adminAssignment.Extent.Text, '$isAdmin = $true')
+        $previewScript = Join-Path $TestDrive 'preview-bootstrap.ps1'
+        [IO.File]::WriteAllText($previewScript, $source, [Text.UTF8Encoding]::new($true))
+        $output = & powershell.exe -NoProfile -File $previewScript -DryRun -ConfigRoot $runtime.FullName @ExtraArgs 2>&1
+        $LASTEXITCODE | Should -Be 0 -Because ($output -join "`n")
+        ($output -join "`n") | Should -Match 'Windows Setup Bootstrap - Preview'
+        $after = @(Get-ChildItem $runtime.FullName -File | Sort-Object Name | Get-FileHash | Select-Object Path, Hash) | ConvertTo-Json
+        $after | Should -Be $before
+    }
+}